title: Identification of new drug targets and resistance mechanisms in Mycobacterium tuberculosis.
abstract: Identification of new drug targets is vital for the advancement of drug discovery against Mycobacterium tuberculosis, especially given the increase of resistance worldwide to first- and second-line drugs. Because traditional target-based screening has largely proven unsuccessful for antibiotic discovery, we have developed a scalable platform for target identification in M. tuberculosis that is based on whole-cell screening, coupled with whole-genome sequencing of resistant mutants and recombineering to confirm. The method yields targets paired with whole-cell active compounds, which can serve as novel scaffolds for drug development, molecular tools for validation, and/or as ligands for co-crystallization. It may also reveal other information about mechanisms of action, such as activation or efflux. Using this method, we identified resistance-linked genes for eight compounds with anti-tubercular activity. Four of the genes have previously been shown to be essential: AspS, aspartyl-tRNA synthetase, Pks13, a polyketide synthase involved in mycolic acid biosynthesis, MmpL3, a membrane transporter, and EccB3, a component of the ESX-3 type VII secretion system. AspS and Pks13 represent novel targets in protein translation and cell-wall biosynthesis. Both MmpL3 and EccB3 are involved in membrane transport. Pks13, AspS, and EccB3 represent novel candidates not targeted by existing TB drugs, and the availability of whole-cell active inhibitors greatly increases their potential for drug discovery.
authors.affiliation: Department of Computer Science and Engineering, Texas A&M University, College Station, Texas, United States of America.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Ioerger
authors.forename: Theresa
authors.initials: T
authors.lastname: O'Malley
authors.forename: Reiling
authors.initials: R
authors.lastname: Liao
authors.forename: Kristine M
authors.initials: KM
authors.lastname: Guinn
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Hickey
authors.forename: Nilofar
authors.initials: N
authors.lastname: Mohaideen
authors.forename: Kenan C
authors.initials: KC
authors.lastname: Murphy
authors.forename: Helena I M
authors.initials: HI
authors.lastname: Boshoff
authors.forename: Valerie
authors.initials: V
authors.lastname: Mizrahi
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Rubin
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Sassetti
authors.forename: Clifton E
authors.initials: CE
authors.lastname: Barry
authors.forename: David R
authors.initials: DR
authors.lastname: Sherman
authors.forename: Tanya
authors.initials: T
authors.lastname: Parish
authors.forename: James C
authors.initials: JC
authors.lastname: Sacchettini
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D016282:Aspartic Acid Endopeptidases / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D055808:Drug Discovery / Q000379:methods*; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D024881:Drug Resistance, Bacterial / Q000235:genetics* / Q000502:physiology; D008958:Models, Molecular; D015394:Molecular Structure; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics*; D048630:Polyketide Synthases / Q000737:chemistry / Q000235:genetics; D017422:Sequence Analysis, DNA / Q000379:methods
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins; C576758:polyketide synthase Pks13, Mycobacterium tuberculosis; D048630:Polyketide Synthases; D016282:Aspartic Acid Endopeptidases